Process of using a masking coating of a telomer of tetrafluoroethylene



June 30, 1964 v E. c. coYNER 3,139,352

PROCESS OF USING A MASKING COATING OF' A TEJOMER OF TETRAFLUOROETHYLENE Orlginal Filed March 18, 1960 50k/'Aff 7'0 55 MASA/o v INV ENT OR EaGf/vf oas/Off? coy/vf,

United States Patent O PROCESS OF USING A MASKING COATING F A TELOMER OF TETRAFLUOROETHYLENE Eugene Casper Coyner, Wilmington, Del., assigner to E. I. du Pont de Nemours and Company, Wilmington,

Del., a corporation of Delaware Continuation of application Ser. No. 15,824, Mar. 18, 1960. This application Aug. 8, 1962, Ser. No. 215,518 6 Claims. (Cl. 117-5.5)

This invention is directed to coatings of telomers of tetrafluoroethylene as antiadhesives for paint, lacquer or other surface coatings. More particularly, the present invention relates to the use of telomers of tetrafluoroethylene to protect surfaces from paint, lacquer or other surface coatings while nearby surfaces are being painted. Usually, when an object is being painted, it is desirable to prevent paint from accidentally adhering to portions of the object or nearby objects. Thus, when painting window frames, it is desirable to prevent paint from adhering to the glass; when painting walls, it is desirable to prevent paint from adhering to the ceiling and floors and, when painting automobiles, it is desirable to prevent paint from adhering to the windows and bright metal littings. A large number of such situations could be mentioned.

There are methods known which will permanently protect a surface from paint. One such method is a permanent coating of polytetrafluoroethylene. Paint does not adhere Well to polytetrafluoroethylene surfaces. For most applications, however, a permanent form of protection is not desired. Means of temporary protection vary with the situation. Large areas only remotely connected with the area being painted can be covered with cloth or paper and smaller areas with masking tape. These methods are adequate when only casual protection is needed, such as floors and furniture in a room being painted. When, however, the area to be protected is close to or adjacent to the area being painted, the use of cloth, paper or masking tape fails to serve .the purpose. To be elfective, the area being protected must be completely sealed from paint or the paint will run under the covering and onto the area being protected. Even when using masking tap, complete sealing is difficult and time consuming to obtain.

An ideal method of protection which meets all pos sible types of application is a subsatnce which could be applied to any surface, completely sealing same from paint, and which could be readily removed later. One approach to this ideal is a now commercially available material consisting of a pigmented vinyl type resin dissolved in an organic solvent. The material may be applied by means of a spray, brush or dipping. It has. several disadvantages however. When applying the material, the same care must be taken, if the areas to be protected and painted are in juxtaposition, as when applying paint for the protective coating must be kept olf the area to be painted. Second, the material is slow drying, causing considerable delay between application and use. Third, the organic solvent is flammable. Fourth, the organic solvent limits its usefulness since organic solvents darnage some surfaces such as varnish. Last, the material cannot be used effectively as a spray since the area covered is determined only by the general characteristics of the spray pattern; any apparatus used to guide the di- 3,139,352 Patented June 30, 1964 ice rection of the spray stream rapidly collects the material impinging on it and becomes heavily coated.

Accordingly, it is an object of this invention to provide a coating composition which is easily removable and which may be readily applied to any type of solid surface, as an undercoating, without the heretofore de scribed adverse effects. Another object is to prevent paint, lacquer or other surface coatings from adhering to the surface coated with this novel composition.

`It is a further object of this invention to provide a novel coating composition which may be readily and rapidly applied by any of the known means for applying liquid dispersions to solids to meet the requirements of different end uses. A still further object is to provide a novel coating composition which does not require an excessive time between application as a coating and use as such. Another object is to provide a coating material which allows ready and complete removal of a lsurface coating that is applied thereover. It is a still further object of this invention to provide an easily removable undercoating composition which is nonammable and that possesses no undesirable physiological properties.

These and other objects will become apparent in the following description and claims.

More specifically, the present invention is directed to a coating of a telomer of tetralluoroethylene on various surfaces obtained by application of a dispersion of said telomer in water or an organic solvent to said surface, said coating enabling the easy removal of subsequently applied surface coatings from the surface by stripping or peeling of the dried surface coating.

Typical materials, the surfaces of which may be coated according to the present invention, include wood, metal, glass, plastics, rubbers, ceramics, painted and other surfaces normally encountered. Representative surface coatings which may be applied include various paints, lacquers, and other surface coatings available in the trade.

The telomers of tetrauoroethylene operable according to the present invention include those telomers obtained from methylcyclohexane, methyl siloxanes, silicones, carbon tetrachloride, chloroform, dialkyl phosphites and alcohols such as methyl alcohol. The method of preparation of these telomers involves telomerizing tetrailuoroethylene with the heretofore-described telogens in a trichlorotriuoroethane solution. Such telomer dispersions include:

The heretofore described telomers consist of molecules of type X(CF2CF2)Y wherein n is an integer of from 10 to yabout 200, i.e., molecular weights of about 1000 to about 20,000. X and Y are the component parts of the telogens, i.e., H and C7H13 from methylcyclohexane, H and a silicon containing group from the siloxanes and silicones, H or Cl and CCl3 from CHC13 and CC14, H and P(O) (OR)2 from dialkyl phosphites and H and R2COH E from aliphatic alcohols (R may be H or an alkyl group). The telomers are obtained as dispersions in trichlorofluoroethane and, in the preferred embodiment, are used as such. In some cases, water `or another organic solvent may be used in place of trichlorotriiluoroethane if desired.

The telomers of tetrailuoroethylene used in the practice of the present invention are waxlike solids which are obtained as dispersione in trichlorotriiiuoroethane (Freon ll3). The solids may be collected and redispersed in water or almost any organic solvent, if desired. Thus, dispersions can be prepared to lit desired requirements. Trichlorotrilluoroethane is, however, the dispersant of choice. The dispersion of telomer can be applied to` the surface to be protected by spraying, painting or dipping.

The telomer dispersions are particularly adaptable to application by an aerosol formulation. When combined with an especially designed spray guide which limits the area covered by the spray, small or quite definite areas can be readily protected. The sprayed material does not adhere to the guide. As pointed out in the present speciiication, other types of materials now available for protecting objects from paint cannot be applied readily via an aerosol type of dispenser. Without a spray guide, the area covered cannot be easily controlled; the commercially available materials tend to adhere to and collect on any spray guide used.

There are numerous uses for the aerosol form of applying the telomers; one of particular interest is the painting of window frames. The telomer dispersion can be applied to the glass adjacent to the frame Without affecting the frame'itself and, at the same time, completely protecting the glass. After painting is complete, the eX- cess paint and telomer coating are readily removed. The use of the telomer dispersione is not limited to the convenient aerosol method of application; the same function can be accomplished by other methods. For instance, if a specific area is to be protected, the telomer dispersion can be painted over a stencil defining the area.

Other uses of the telomers include repainting automobiles, where the glass and bright metal fittings can be easily protected while the new iinish is applied; protection of trim and other surfaces While painting houses; the protection of handles, drawer pulls, etc. when refinishing furniture; the protection of bright metal objects when painting boats. The telomer dispersions may be applied to and are effective on almost all non-porous surfaces. The dispersing liquid of choice is trichlorotriuoroethane since its toxicity is very low, it is nonflammable, it evaporates rapidly and it is harmless to almost all surfaces. Other dispersing liquids can he used if, for some reason, the one of choice is unsuitable. Thus, if a less volatile liquid -is desired, water, 1,2-diliuorotetrachloroethane or perchloroethylene can be used. Other organic solvents such as toluene, xylene or glycols can be used but are less desirable due to` their flammability, toxicity and harmfulness to some surfaces.

The telomer compositions of the present invention form durable but not permanent coatings. After serving their purpose, they are readily removable such as by washing with soap and water. Application of the dispersion to the surface is the only treatment required. The surface coating can be buffed but it serves no necessary function.

The primary property/,of coatings of the subject telomers is that paint coatings will not adhere thereto. Several useful applications of this property have been described; many others will be apparent to those familiar with the art. The examples which follow. demonstrate the usefulness of the telomer coatings. Comparisons are made with other methods of protecting surfaces from paint adhesion. These comparisons demonstrate the superior properties of the telomer coatings. These examples are for sake of illustration and are not meant to limit the scope of the invention.

tion follow.

EXAMPLE 1 Coupons of tin-coated steel of the type used for manufacture of motor oil cans were prepared. These consisted of a strip of metal 6-8 inches long and 11/2 inches wide, formed to a sharp point at the last inch of one end. Any adhering oil and Wax was removed with trichlorotriuoroethane before" use. The protective coatings were applied as indicated in Table I which follows and allowed to dry; then they were immersed in an alkyd enamel to a depth of four inches for iive minutes and hung up to drain and dry. The ease of removal of the paint is indicated in Table I.

Table I Protective Coating Application Adhesion of Paint 1. Telomer,u 1% A I. aerosol-- Sprayed on onee Easily removed. 2. Telomer,n 11% A.I. disper- Dipped once Do.

persion in CgFaCla. f 3. Paraflm Wax, 1% Al. Sprayed on, buffed. Adheres rmly.

aeroso 4. Paraflin Wax Rubbed on 3 Do.

times buded. 5. Carnanba waxb Rubbed on 2 Do.

times, bufled. 6. Silicone DC 200 v Liquid rubbed on Do. 7. Silicone DC 550 s..- do Do. 8. Kel-F fluid d do Do. 9. Kel-F grease d Grease rubbed on- Do. 10. Fluoropolymer e.- Dipped once Adhesion slightly weakened. 11. Fluoropolymerl Do. 12. Polytetraiiuoroethylene Easily removed.

60% A. I. dispersion. 13. Polytetranoroethylene do Slightly weakened.

15% A.I. dispersion.

h Tetraluoroethylene telomer derived from methyleycloexalte.

b A wax derived from vegetable sources.

c Polysilicones of viscosity in centistokes 200 and 550.

dPolymers of chlorotrifluoroethylene of liquid and greaselike consistency.

GA dispersion in aqueous acetone of a hom'opolymer of CsF17SO2N(CH7)CHzCH2O2C-CH=CH2 CODaIliDg a. cationic surfactant.

f Same as (0) above, except it contains an anionic surfactant.

Dries very slowly.

The results of these experiments demonstrate the superiority of telomers as antiadhesives for paint. Item 12 also acts as antiadhesives for paint but note the very high concentration of active ingredient; item 13 indicates that the high concentration is necessary. Two other materials, items l0 and l1, slightly weakened the paint adhesion but not enough to be useful.

EXAMPLE v n Microscope slides were cleaned by wiping. They were then treated with the various protective agents as shown in Table II and allowed to dry. An alkyd enamel was then applied and allowed to dry. The results are shown in Table II.

Table Il Protective Coating Application Adhesion oi Paint 1. Telomen 11% Al, disper- Dipped twice Easily removed.

sion in CgFaCla. Y 2. Silicone DC 550 b Liquid rubbed en Adheres lirmly. 3. Kel-F fluide do Do. 4. Paralin wax, 1% A.I. Sprayed on and Adheres strongly.

aerosol. buied. 5. Control Adheres firmly.

Pieces of new plywood (2 X 2" x IAN) were treated with the protective agent in the. manner shown in Table successful coating.

III. The surfaces were then painted with an alkyd enamel and allowed to dry. The results are shown in Table HI.

Table Ill Protective Coating Application Adhesion of Paint 1. Tclomer 11% Al. disper- Dipped and dried Easily removed.

sion in CzFsCls. twice. 2. Silicone DC-550 b Rubbed on twlce Adhercs firmly. 3. Kel-F liquidD do Do. 4. Paraftin wax, 1% A.I. Sprayed on tw1ce Do.

aerosol. 5. Control Do.

a See footnote (n), Table I. b See footnote Table I. 15 See footnote (d), Table I.

This series of experiments demonstrates that the telomer is superior to the other materials tested in preventing the adhesion of paint to wood. It was, in fact, the only EXAMPLE rv A surface (steel) previously covered with a firmly adhering coat of alkyd enamel was dipped into an 11% A.I. dispersion of telomer. The surface was then covered with alkyd enamel and allowed to dry. The second coat of enamel was readily peeled away from the first coat. Without the coating of telomer, the second coat of enamel firmly adheres to the first.

After the layer of enamel had been peeled oif in the above test, the protective coating was removed by brisk rubbing. Then, the surface was covered with enamel and allowed to dry. It adhered firmly to the first coat of enamel.

EXAMPLE V Coupons of tin-coated steel, as described in Example I, were coated with various telomers of tetrafluoroethylene as described in Table IV. They were then immersed in alkyd enamel as in Example I. The results on paint adhesion are shown in Table 1V.

Table I V Telomer of TFE Application Adhesion of Paint 1. Methylcyclohexaneb Dipped once Easilyremoved. 2. Dicthyl Phosphite 8% Al. in .do Do.

C3F3C13. 3. Methyl alCOhOl 7% A.I. in ---dO D0.

CrFsCl. 4. Polysiloxane 8% A.I.i11C2F3Cl3- do Do.

TFEztetrafluoroethylene. The telogen is indicated,

b Item 2, Table I.

It is to be understood that any of the heretofore described telomers of tetrafluoroethylene may be substituted in the preceding examples to give substantially the same results. In addition, substantially identical results are achieved when lacquer is utilized instead of paint and when the material of the surface varies as described. Mixtures of the heretofore-described telomers are also operative to produce a removable coating composition as herein described.

In addition to the preceding examples utilizing telomers of tetraiiuoroethylene as an antiadhesive for paint, it is also to be understood that these telomers are useful as antiadhesives for other purposes. Thus, they are useful in preventing the rubber sealing gaskets of refrigerator doors from sticking to the body of the refrigerator. They are also useful in preventing unused postage stamps and labels from sticking to each other or .to other papers. They may be used to prevent materials from sticking to finishes of boats and in preventing mud from sticking to shoes. They are also useful in preventing materials from sticking to process equipment such as blenders, conveyor belts, chutes and calenders. They are also useful in preventing paint accumulation in spray booths.

An understanding of the invention will be further aided 75 `bine to form the process.

-by reference to the accompanying drawing'which describes the series of steps necessary to carry out the novel process of the subject invention. The process is illustrated in the drawing by showing a substrate as it would appear after each step in the series of steps which com- The sequence in which the steps of the process are carried out follows the direction of the arrowsin the drawing. With reference to the drawing, the top sketchof the substrate shows the surfaces of the substrate to be coated and the surface to be masked or protected from the coating. The next sketch depicts the substrate after the telomer masking coating has been applied to the designated surface.A The waxlike telomer coating is applied to the substrate as a dispersion in a solvent. The solvent is subsequently removed by evaporation. The telomer dispersion can be applied to the surface of the substrate by any conventional means, such as by brushing or painting the dispersion on the surface, or by dispensing the dispersion from an aerosol container. The third sketch of the substrate shows the substrate after the permanently adhering surface coating has been applied to the surfaces designated to be coated. The fourth sketch of the substrate depicts the substrate during the removal of the telomer masking coating. The telomer coating can be removed by any convenient method, such as peeling or chipping the coating. Any permanently-adhering surface coating which inadvertently fell on the telomer masking coating is easily removed with the masking coating as illustrated in the drawing. The last sketch of the substrate shows the finished product with the desired surfaces coated and the adjoining surface uncoated.

This application is a continuation application of my copending application, Serial No. 15,824, filed March 18, 1960, now abandoned.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an'exclusive property or privilege is claimed are dened as follows:

l. A process which comprises coating a portion of a surface with a dispersion of a wax-like telomer of tetrafluoroethylene in a volatile solvent, said telomer having a molecular weight Within the range of 1,000 to about 20,000, and allowing said solvent to evaporate thereby forming a temporary antiadhesive telomer coating on said portion of said surface, followed by applying to the adjacent non-telomer coated portion of said surface a thin layer of a permanently-adhering surface coating and allowing said surface coating to set, and thereafter removing from said surface said telomer coating and such portion of said permanently-adhering surface coating as may be applied thereon when applying said permanently-adhering surface coating.

2. A process which comprises coating a portion of a surface with a dispersion of a wax-like telomer of tetrafluoroethylene in a volatile solvent, said telomer having a molecular weight within the range of 1,000 to about 20,000, and allowing said solvent to evaporate thereby forming a temporary antiadhesive telomer coating on said portion of said surface, followed by applying to the adjacent non-telomer coated portion of said surface a layer of permanently-adhering paint and allowing said paint to harden, and thereafter removing from said surface said telomer coating and such portion of said permanently-adhering paint as may be applied thereon when applying said permanently-adhering paint.

3. The process according to claim 1, wherein said telomer of tetrauoroethylene is prepared by telomerizing tetrauoroethylene with diethyl phosphite in a trichlorotriiiuoroethane solution.

4. The process according to claim 1, wherein said telomer of tetrauoroethylene is prepared by telrneriz'- ing tetrauorethylene with methyl alcohol in a trichlorotriuoroethane solution.

5. The process according to claim 1, wherein said telorner of tetrauoroethylene is prepared by telomerizing tetrauoroethylene with a polysiloxane in a trichlorotriuoroethane solution.

6. The process according to claim 1, wherein said telomer of tetraluoroethylene is prepared by telomerizing tetrauoroethylene with methylcyclohexane in a trichlorotrifluoroethane solution.

References Cited in the file of this patent UNITED STATES PATENTS 2,139,640 Mall et al Dec. 6, 1938 2,411,159 Hanford Nov. 19, 1946 2,440,800 Hanford et a1 May 4, 1948 2,468,664 Hanford et al Apr. 26, 1949 2,488,446 Swiss Nov. 15, 1949 2,562,117 Osdal July 24, 1951 2,562,547 Hanford et al July 31, 1951 o Miller Jan. 25, 1955 Dittman et al. Apr. 5, 1955 Hochberg June 7, 1955 W011i Oct. 14, 1958 Hochberg ,Oct. 6, 1959 Baer Apr. 26, 1960 Warrick Nov. 1, 1960 Brady Dec. 4, 1962 Spiegler Dec. 18, 1962 FOREIGN PATENTS Great Britain Jan. 1, 1947 Great Britain Ian. 23, 1957 Great Britain Nov. 13, 1957 Canada July 24, 1954 Canada Dec. 27, 1955 OTHER REFERENCES Masks, Modern Plastics, vol. 31, No. l, September 20 1953, pp. 98-99. Y 

1. A PROCESS WHICH COMPRISES COATING A PORTION OF A SURFACE WITH A DISPERSION OF A WAX-LIKE TELOMER OF TETRAFLUOROETHYLENE IN A VOLATILE SOLVENT, SAID TELOMER HAVING A MOLECULAR WEIGHT WITHIN THE RANGE OF 1,000 TO ABOUT 20,000, AND ALLOWING SAID SOVLENT TO EVAPORATE THEREBY FORMING A TEMPORARY ANTIADHESIVE TELOMER COATING ON SAID PORTION OF SAID SURFACE, FOLLOWED BY APPLYING TO THE ADJACENT NON-TELOMER COATED PORTION OF SAID SURFACE A THIN LAYER OF A PERMANENTLY-ADHERING SURFACE COATING AND ALLOWING SAID SURFACE COATING TO SET, AND THEREAFTER REMOVING FROM SAID SURFACE SAID TELOMER COATING AND SUCH PORTION OF SAID PERMANENTLY-ADHERING SURFACE COATING AS MAY BE APPLIED THEREON WHEN APPLYING SAID PERMANENTLY-ADHERING SURFACE COATING. 